Search Results (4)

This study evaluated the influence of different male date palm cultivars, distinguished by their chloroplast haplotypes, on pollen quality, pollination efficiency, metaxenia effects, and gene expression during fruit development. Chloroplast DNA analysis of 37 male trees revealed multiple haplotypes, from which cultivars B25, P8, C22, and B46 were selected for further investigation. Pollen viability varied significantly among cultivars, with P8 and B25 exhibiting the highest germination rates and pollen tube elongation, while C22 showed the lowest. These differences correlated with pollination success: P8 and B25 achieved fertilization rates near 99%, whereas C22 remained below 43%. Pollination outcomes also varied in fruit traits. Despite its low pollen performance, C22 induced the production of larger fruits at the Bleh (Kimri) stage, potentially due to compensatory physiological mechanisms. Phytochemical profiling revealed significant cultivar effects: fruits from B25-pollinated trees had with lower moisture and polyphenol content but the higher sugar levels and soluble solids, suggesting accelerated maturation. Ripening patterns confirmed this finding, with B25 promoting the earliest ripening and B46 causing the most delayed. Gene expression analysis supported these phenotypic differences. Fruits pollinated by P8, B25, and B46 exhibited elevated levels of cell-division-related transcripts, particularly the PdCD_1 gene (PDK_XM_008786146.4, a gene encoding a cell division control protein), which was most abundant in P8. In contrast, fruits from C22-pollinated trees had the lowest expression of growth-related genes, suggesting a shift toward cell expansion rather than division. Overall, the results show the critical role of male genotype in influencing fertilization outcomes and fruit development, offering valuable insights for targeted breeding strategies at enhancing date palm productivity and fruit quality. Full article

Skin separation (puffiness) is a critical physiological disorder that significantly reduces the date palm (Phoenix dactylifera L.) fruit’s visual appearance and quality. The objectives of this study were to analyze fruit anatomy in skin-separated and normal date palm (var. Mejhoul) fruit and to assess the microclimatic conditions (temperature and relative humidity) during the fruit developmental stages and their association with skin separation. Fruit anatomy analysis was carried at different growth stages (Kimri-Khalal, Khalal, Rutab and Tamr) for two growing seasons. In addition, microclimatic conditions (specifically, temperature, and relative humidity) as well as soil moisture content were assessed across the study period 2020 and 2021. The anatomical analysis of the date palm fruit revealed that the exocarp or skin (cuticle, epidermis, hypodermis) thickness were quite similar across the developmental stages and over the study period (2020, 2021). Conversely, significantly more sclereid cells were found in skin-separated fruit (compared to normal fruit) at the Tamr stage. At that stage (Tamr), the percentage increase in sclereid cell number in skin-separated fruit ranged from 34–183%, sclereid clusters number 23–92%, cluster area 37–206%, and cluster perimeter 25–64%, as compared to normal fruit. In addition, sclereid cells at skin-separated areas of the fruit were clustered together, forming a chain of aggregates underneath the fruit skin, and were closer (42–50%, than normal) to the cuticle, leading to the partial separation of the exocarp from the fruit mesocarp. Although the weather data were similar across the growing seasons (temperatures, 33–34 °C; relative humidity, 45–46%), skin separation occurred in 14–15% of total fruit in 2020 and 30–34% in 2021. Therefore, we believe that skin separation disorder is not as heavily weather dependent as it seems to have been thought. In conclusion, changes in microclimate conditions were not the conclusive component for inducing the skin separation physiological disorder in date palm fruit. Further studies are required to identify the main factors that stimulate the development of sclereid clusters aggregates and the potential of agricultural practices to reduce skin separation. Full article

The study investigated the phenols, sugar and the antioxidant capacities of date fruit extracts obtained by organic solvents and by hydrothermal treatment from six different Algerian cultivars at two ripening stages for the first time. The analyzed cultivars exhibited potent antioxidant properties (ferric reducing antioxidant power (FRAP), 1,1-Diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) scavenging capacities) and different phenols regardless of the solvents and the maturity stages. About 18 phenols were identified and quantified, mainly in the hydrothermal extracts. The earlier stages were characterized by high amounts of o-coumaric acid, cinnamic acid and luteolin, with a noticeable absence of quercetin. The tamr stage presented the highest sugar content (78.15–86.85 mg/100 mg dry weight (DW)) with an abundance of glucose. Galactose was present only in some cultivars from the kimri stage (tamjouhert). Uronic acids were mostly detected at the tamr stage (4.02–8.82 mg gallic acid equivalent/100 mg dried weight). The obtained results highlight the potential of using date fruit extracts as natural antioxidants, especially at industrial scales that tend use hydrothermal extraction. Full article

Date palm (Phoenix dactylifera) is considered to be a highly important food crop in several African and Middle Eastern countries due to its nutritional value and health-promoting properties. Microbial contamination of dates has been of concern to consumers, but very few works have analyzed in detail the microbial load of the different parts of date fruit. In the present work, we characterized the fungal communities of date fruit using a metagenomic approach, analyzing the data for differences between microbial populations residing in the pulp and peel of “Medjool” dates at the different stages of fruit development. The results revealed that Penicillium, Cladosporium, Aspergillus, and Alternaria were the most abundant genera in both parts of the fruit, however, the distribution of taxa among the time points and tissue types (peel vs. pulp) was very diverse. Penicillium was more abundant in the pulp at the green developmental stage (Kimri), while Aspergillus was more frequent in the peel at the brown developmental stage (Tamer). The highest abundance of Alternaria was detected at the earliest sampled stage of fruit development (Hababauk stage). Cladosporium had a high level of abundance in peel tissues at the Hababauk and yellow (Khalal) stages. Regarding the yeast community, the abundance of Candida remained stable up until the Khalal stage, but exhibited a dramatic increase in abundance at the Tamer stage in peel tissues, while the level of Metschnikowia, a genus containing several species with postharvest biocontrol activity, exhibited no significant differences between the two tissue types or stages of fruit development. This work constitutes a comprehensive metagenomic analysis of the fungal microbiome of date fruits, and has identified changes in the composition of the fungal microbiome in peel and pulp tissues at the different stages of fruit development. Notably, this study has also characterized the endophytic fungal microbiome present in pulp tissues of dates. Full article